You're right about all of those
My point is that we don't really have labels for those "generations" which are typically vin based or at least have a name "EF" for Honda, "e92" bmw, "993" Porsche etc, nor is the community keenly aware of them.
Typically those generational distinctions imply changes which makes parts not interchangeable so they need an identifier when being sold. For Caterham it matters in some very specific aspects. Imperial vs Metric matters for some things like roll cages but not many others. Dedion vs solid rear matter for rear end but many other things are still interchangeable.
Maybe that's why we don't have these distinctions in the community, because they matter so much less?